Which of the following statements regarding the first law of thermodynamics is correct?

Find the value of the equilibrium constant $(K)$ of a reaction at 300 K , when standard Gibbs free energy change is $-25 \mathrm{~kJ} \mathrm{~mol}^{-1}$ ? (Consider $R=8.33 \mathrm{Jmol}^{-1} \mathrm{~K}^{-1}$ )

What will be the $\Delta U$ value, when one mole of oxygen $\left(\mathrm{O}_2\right)$ is going from $-20^{\circ} \mathrm{C}$ to $40^{\circ} \mathrm{C}$ at constant volume? (Molar heat capacity for oxygen $\simeq 20.8 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ )

$\Delta H$ and $\Delta S$ for a reaction are $+30.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and 0.06 $\mathrm{kJK}^{-1} \mathrm{~mol}^{-1}$ at 1 atm pressure. The temperature at which free energy change is equal to zero and nature of the reaction below this temperature are